1. Field of the Invention
The present invention relates generally to motion capture systems. More particularly, the present invention relates to motion capture systems using motion databases.
2. Background Art
Motion capture can be productively applied to many different fields, including entertainment applications such as video games and movies, medical applications such as physical therapy, monitoring and rehabilitation, physical training applications such as martial arts training, and other areas. In particular, the low cost of MEMS devices such as accelerometers have effectively lowered the barrier of entry for utilizing motion capture. The Wii Remote by Nintendo has provided one visible example harnessing the power of small, lightweight, and low cost accelerometers for capturing the key actions of a video game player.
Unfortunately, the level of motion capture provided by simple devices such as the Wii Remote is insufficient to reproduce detailed coordinated motions of the human body. Since the Wii Remote only provides one point of measurement, it can only track, for example, the hand or arm motions of the user. To retrieve a more detailed range of readings such as for the entire upper body or whole body motion, a more advanced motion capture system is necessary.
One solution is simply to increase the number of accelerometers to provide acceleration readings from several points on a user's body. Unfortunately, with accelerometers alone, it is difficult to accurately calculate the position of the accelerometers for accurate reproduction of user movements. If a straightforward double integration is applied to the acceleration readings to produce positional readings, continual uncorrectable drift inherent in the double integration will skew the positional readings. While solutions to calculating positions have been advanced, including simple solutions such as the infrared “sensor bar” used by the Wii Remote or more advanced solutions such as acoustic-inertial trackers and inertial measurement units (IMUs) using accelerometers, gyroscopes, and magnetic sensors, such solutions are either too simple to provide sufficient positional granularity or too complex and expensive, raising the costs of implementation and thus the barrier to usage. While camera based capture systems exist that can provide accurate positional readings, most of these systems are uncomfortable to use, cumbersome to setup due to complex environmental instrumentation requirements, and prohibitively expensive for general adoption.
Accordingly, there is a need to overcome the drawbacks and deficiencies in the art by providing a cost effective, wearable, and user-friendly motion capture system capable of reproducing a full range of human body motions.